function Imagen_Aleatoria() {

var cc1 = Math.floor(Math.random() * collage1.length)
var cc2 = Math.floor(Math.random() * collage2.length)
var cc3 = Math.floor(Math.random() * collage3.length)
if (cc1 == 0) { cc1 = 1 } 
if (cc2 == 0) { cc2 = 1 } 
if (cc3 == 0) { cc3 = 1 } 

	 document.write ('<span class="marco3"><img src="'+collage1[cc1]+'" width="150" height="150" alt="'+pie1[cc1]+'" border="0" /></span>');
	 document.write ('<span class="marco3"><img src="'+collage2[cc2]+'" width="150" height="150" alt="'+pie2[cc2]+'" border="0" /></span>');
	 document.write ('<span class="marco3"><img src="'+collage3[cc3]+'" width="150" height="150" alt="'+pie3[cc3]+'" border="0" /></span>');

}

// Bibliotecas
var collage1=new Array(); 
collage1[1] = '/seccion/ba/graf/collage1a.jpg';
collage1[2] = '/seccion/ba/graf/collage1b.jpg';
collage1[3] = '/seccion/ba/graf/collage1c.jpg';
collage1[4] = '/seccion/ba/graf/collage1d.jpg';
collage1[5] = '/seccion/ba/graf/collage1e.jpg';

var pie1=new Array(); 
pie1[1] = 'Biblioteca Nacional de la Rep&uacute;blica Argentina';
pie1[2] = 'Biblioteca Nacional de M&eacute;xico';
pie1[3] = 'Biblioteca Nacional del Per&uacute;';
pie1[4] = 'Biblioteca Nacional, Brasil';
pie1[5] = 'Biblioteca Nacional de Chile';

// Paisajes
var collage2=new Array(); 
collage2[1] = '/seccion/ba/graf/collage2a.jpg';
collage2[2] = '/seccion/ba/graf/collage2b.jpg';
collage2[3] = '/seccion/ba/graf/collage2c.jpg';
collage2[4] = '/seccion/ba/graf/collage2e.jpg';
collage2[5] = '/seccion/ba/graf/collage2f.jpg';
collage2[6] = '/seccion/ba/graf/collage2g.jpg';

var pie2=new Array(); 
pie2[1] = 'Monte Aconcagua';
pie2[2] = 'Pir&aacute;mide de Cholula';
pie2[3] = 'Machu Picchu';
pie2[4] = 'Cataratas de Iguaz&uacute;';
pie2[5] = 'Costa del Caribe';
pie2[6] = 'Ruinas de Tikal';

// Monumentos
var collage3=new Array(); 
collage3[1] = '/seccion/ba/graf/collage3a.jpg';
collage3[2] = '/seccion/ba/graf/collage3b.jpg';
collage3[3] = '/seccion/ba/graf/collage3c.jpg';
collage3[4] = '/seccion/ba/graf/collage3d.jpg';
collage3[5] = '/seccion/ba/graf/collage3e.jpg';

var pie3=new Array(); 
pie3[1] = 'Fortaleza El Morro';
pie3[2] = 'Monumento Ecuatorial';
pie3[3] = 'Palacio de Moneda';
pie3[4] = 'Catedral Metropolitana de M&eacute;xico';
pie3[5] = 'Pir&aacute;mide de Mayo';

Imagen_Aleatoria()